David Bennett looked like a “pretty healthy 57-year-old except that his heart was failing,” recounts his physician, Dr. Bartley Griffth. In late November of 2021, he was transferred to the University of Maryland Medical Center where he spent the next two weeks under intensified care. And in spite of “multiple medications to drive his heart, and a device called a balloon pump that was inserted through the groin to make his heart more efficient, he just did not have enough blood flow to sustain his life. So, he was placed on another treatment called Extracorporeal Membrane Oxygenation (ECMO), which is a bulky machine that does all the work of the heart and the lungs,” said Dr. Griffith in an interview. For more than 50 days leading to his transplant surgery, he was stuck in bed connected to this bizarre machine, ECMO, tubes going in and out carrying stale blood on one end and freshly oxygenated blood on another. He did not qualify for a human heart transplant because, due to the deficit in human heart supply, one of the criteria requires young age. The pig’s heart transplant, never attempted in the history of clinical science, was his last and only resort to which, when his doctors explained, he replied: “I do not want to die.”
Immortality has been a topic of numerous philosophical debates and a common theme throughout religion and works of literature. The story of Adam and Eve and the fall of humankind into the bondage of sin and death has its foundation in the loss of immortality. Christianity is, in fact, based on the idea of eternal resurrection: a belief that one who is good gets an after-life of utter tranquility in a world without pain and suffering. Furthermore, characters of immortal beings have appeared as main protagonists in The Man from Earth (2007) and Old Guard (2021). Immortality is something humankind has dreamed of ever since the very beginning. Hence, it is fittingly described as the unquenchable “thirst not to die,” or such has been said until recently. Due to the advancements in scientific studies on telomerase, aging is starting to be viewed as a curable disease, and technologies such as cryogenics and xenotransplantation are pushing the boundary of death.
The word xenotransplantation stems from Greek “xenos-” meaning “stranger” or “alien”. Xenotransplantation, therefore, means the transplantation of foreign organs usually from an animal into a human, and it has long been thought as a suitable solution for organ shortages. The first ever documented operation was a xenotransfusion which was practiced by a French physician, Jean-Baptiste Deny, on June 15, 1667. He transfused a sheep’s blood into his first two patients, who somehow survived, which is presumably because he only administered a negligible dose not enough to trigger any allergic reaction. However, his third operation ended up with the death of his patient, and the French court has put a ban on animal blood transfusion thereafter. There are numerous other historical records on similar practices such as the transplantation of chimpanzee kidneys in 1963, chimpanzee hearts in 1964, chimpanzee livers in 1970, but virtually all have been failed attempts. Most patients died within a few days after the operation, and the longest period of survival was nine months. This highlights the complexity of the human’s immune system and the technological inability to engineer a foreign organ to be fully accepted by a human body. There have been, however, a few minor successes such as the transplantation of pig’s skin to cure a severe burn and pig’s pancreatic cells to cure type-1 diabetes.
As the life expectancy of modern-day humans continues to increase, people are more prone to live with “chronic diseases who may ultimately require organ transplantation for the treatment of their condition,” according to Reinsurance Group of America. While xenotransplantation has seen little to no success so far, the demand is quite clear and pharmaceutical companies are investing astronomical amounts of money in R&D for transgenic animal organs that are compatible with the human immune system. Novartis, a pharmaceutical company based in Switzerland, “plans to spend more than a billion USD for research and infrastructures where pigs could be grown in a germ-free environment,” according to Nature. Currently, numerous investments are being made and active research is being conducted all around the world. With the advancement of medical science and a better understanding of human immunology, the academia, is taking methodical steps towards human trials, ultimately to save thousands of lives currently in line waiting for organ donation.